.btn {
    border: solid 1px #bdbdbd;
    padding: 7px 15px;
    background: #ffffff;
    color: #616161;
    border-radius: 7px;
    cursor: pointer;
}

.btn:hover {
    border: solid 1px #212121;
}

.btn-danger {
    color: #f5f5f5;
    background: #e64a19;

}

.btn-danger:hover {
    border: solid 1px #bf360c;
}

.hide {
    display: none;
    visibility: hidden;
    opacity: 0;
}

.todo-container {
    margin: 100px auto;
    width: 500px;
    position: relative;
    padding: 10px;
    border: solid 1px #d4d4d4;
    border-radius: 7px;
    background-color: #f5f5f5;
}

.todo-header {
    box-sizing: content-box;
    margin-bottom: 10px;
}

.todo-header input {
    border: solid 1px #9e9e9e;
    border-radius: 5px;
    padding: 0 10px;
    height: 34px;
    width: 480px;
}

.todo-item-warp {
    position: relative;
    cursor: pointer;
    margin-bottom: 10px;
    border: solid 1px #bdbdbd;
    border-radius: 7px;
    background-color: #ffffff;
}

.todo-item {
    position: relative;
    padding: 10px;
    border-bottom: solid 1px #bdbdbd;
}

.todo-item:last-child {
    border-bottom: none;
}

.todo-item:hover {
    background-color: #eeeeee;
}

.todo-item input[type="checkbox"] {
    margin-right: 15px;
}

.todo-item .btn {
    opacity: 0;
    position: absolute;
    right: 10px;
    top: 5px;
}

.todo-item:hover .btn {
    opacity: 1;
    animation: fade 1s none;
}

.todo-footer {
    position: relative;
    padding: 10px 0;
}

.todo-footer input[type="checkbox"] {
    margin: 0 15px;
}

.todo-footer .btn {
    position: absolute;
    right: 10px;
    top: 5px;
}

/* 隐藏 --> 显示 */
@keyframes fade {
    0% {
        opacity: 0;
    }
    25% {
        opacity: 0.25;
    }
    50% {
        opacity: 0.5;
    }
    75% {
        opacity: 0.75;
    }
    100% {
        opacity: 1;
    }
}
